yielding between 10% and 90% mortality in 24h) were used to determine LC50 and LC90 values. Batches of 20 first, second,third and fourth instar larvae were transferred by means of strainers, droppers to Schott Duran beakers, each containing 200 mL of triple deionized water. Unhealthy or damaged larvae or pupae were removed and replaced. The depth of
the water in the cups or vessels should remain between 5 cm and 10 cm, deeper levels may cause undue mortality.
2.4. Statistical analysis
Data from all replicates have been pooled for probit analysis[15]. The LC50 and LC90 values were calculated from a log dosage probit mortality regression line using computer software programs IBM SPSS 19.0. The bioassays have been repeated at least three times, using new solutions and different batches of larvae each time. Standard deviation
or confidence intervals of the means of LC50 values were calculated and recorded.